The present invention relates generally to tumbler wheels for use in combination locks. More specifically, the present invention relates to adjustable tumbler wheel constructions which are used in adjustable combination locks.
Combination locks having tumbler wheels which may be adjusted to provide different combinations are experiencing widespread and increasing use. An adjustable combination lock has many apparent advantages. For example, if the combination becomes to widely known, rather than replacing the lock, the combination is simply changed. Further, the security provided by the combination lock may also be increased by frequent combination changes to prevent a would-be thief from memorizing any one combination. Another major advantage of adjustable combination locks is the convenience provided by allowing any given individual to set the combination to a desired sequence of numbers which for one reason or another may be easily memorized.
In general, adjustable combination locks utilizing tumbler wheels include a combination dial which is attached to a drive shaft. Typically, three tumbler wheels are mounted on the drive shaft with only one tumbler wheel being directly driven by the drive shaft. The other two wheels are indirectly driven by a series of tabs and/or grooves communicating between the tumbler wheels. The basic adjustable tumbler wheel includes an outer gate ring which has a gate or indention formed in the periphery thereof. A latch bolt lever or other actuation bar rides around the periphery of the gate ring. Actuation of the latch bolt lever to unlock the combination lock can only be accomplished once the gates of all gate rings are aligned. Alignment of the gate rings is accomplished by selective rotation of the drive shaft to selectively drive the gates into alignment. The gate rings are mounted concentrically about inner drive rings. In a non-adjustable combination lock, the drive ring and gate ring would generally be integral members whose position relative each other is fixed. In adjustable combination locks, provision is made for rotating the drive ring relative the gate ring to move the gate to varying positions around the drive ring to allow combination adjustment.
A typical adjustable tumbler wheel construction is disclosed in U.S. Pat. No. 4,142,388 issued to Peter J. Phillips on Mar. 30, 1977. The adjustable tumbler wheel of Phillips is typical of prior art adjustable tumbler wheels which require special tools for combination changes. Phillips requires the use of a special half moon shaped tool which is inserted into the gate ring where it is turned to move a locking member from its engaged position with the drive ring to allow rotation of the drive ring relative to the gate ring to accomplish combination changes. Another adjustable tumbler ring construction is disclosed in my co-pending U.S. Pat. application, Ser. No. 152,195 filed on May 22, 1980 and now U.S. Pat. No. 4,312,199. This particular adjustable tumbler wheel construction utilizes a lightweight plastic gate ring which is mounted on the drive ring by way of a lock ring which is typically employed for such purposes. Further, the means for providing adjustment of the drive ring relative the gate ring are provided by a cam member which also requires the use of a special tool.
It is therefore, desirable to provide a simple lightweight adjustable tumbler wheel construction where the gate ring can be mounted quickly and conveniently on the drive ring and wherein the gate ring may be adjusted about the drive ring quickly, conveniently and reliably without the use of special tools.